Dathomir - 99% explored with 100% in all regions

I'm struggling to unlock the "A Galaxy Far, Far Away" trophy ("Complete all of BD-1's holomaps") because Dathomir is stuck on 99% explored. I know what you're thinking - I've missed a Force Echo or something - except I haven't. The database is 100% complete, and all regions in the area are marked as "Explored". All other planets are 100% explored.

The only thing I can find is an R3 radio call prompt in Witches Horn - if I press R3, the prompt disappears and I don't hear any call. I can trigger this prompt every time I revisit that area (where you first fight Gorgara). I'm not sure if this is a bug or a technical issue, but I'd appreciate some advice, thanks.